One of the regular Billion Monkey things I often notice is this nice thing they do with their fingers:

So imagine my amazement when I spied this snap, of Jackie D, apparently taking a digital photograph with a sandwich:

All Jackie D is doing, of course, is holding a sandwich. She is doing the finger thing not because she is photographing anything with the sandwich, but because the sandwich is being photographed (rather than just Jackie D) , and Jackie D wants to be sure that it is totally visible to the actual camera.

In each case, the fingers are like that to make sure no light waves are interrupted.